Function pio_parse_warnings 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn pio_parse_warnings(
    net: *const PioNetwork,
    warnbuf: *mut c_char,
    warnlen: usize,
) -> usize

Read fidelity warnings attached at parse time, \n-joined into warnbuf (truncated to fit; NULL/0 to skip). Returns the warning count; 0 for a NULL handle. Empty for formats whose readers are total.